1. Field of the Invention
The present invention relates to an aqueous ink and an aqueous ink set each containing a water-insoluble coloring material. More specifically, the present invention relates to a recording method and a recording apparatus each using an ink-jet recording system; and an aqueous ink suitable for an image-forming method.
2. Related Background Art
Ink containing, as a coloring agent, a water-insoluble coloring material such as a pigment (pigment ink) has been conventionally known to provide an image excellent in fastness properties such as water resistance and light resistance. Various techniques have been recently proposed for the purpose of increasing the image density of an image formed by means of such ink.
For example, there has been proposed the use of an ink containing self-dispersion carbon black and a specific salt to achieve an additional increase in image density (see, for example, JP-A-No. 2000-198955). A technique has also been proposed, which involves: causing an ink-jet recording ink, which is a composition containing a pigment, polymer fine particles, a water-soluble organic solvent, and water, and a polyvalent-metal-salt-containing aqueous solution to adhere to a recording medium; and causing the ink composition and the polyvalent-metal-salt-containing aqueous solution to react with each other to form a high-quality image (see, for example, JP-A-No. 2000-063719). In each of those techniques, a pigment present in ink in a dispersed state is forcedly flocculated at the surface of a recording medium to suppress the permeation of the pigment into the recording medium, thereby obtaining an image with an increased density.